GASTEROPODA IWPEROBRANCHIATA. *O 



FLABELLINA, Cuv. 



The tentacula of the fiolkHae, with radiating rectiform branchiae, 

 Mipported by five or six pedicles on each side; they are closely allied 

 to the Glauci, and in fact to all tho Nudibranchiata, whose branchiae 

 are situated on the sides of the back*. 



TERGIPES, Cuv. 



The form of the Eolidiae, but only two tentacula, with a range of 

 cylindrical branchiae on both sides of the back, each of which is ter- 

 minated by a little sucker or cup, and which are used by the animal 

 t, to walk on its back. The species known are very smallf. 



BUSIRIS, Risso. 



The body oblong, and back convex; two filiform tentacula, and 

 behind them, on the nape, two plumiform branchiae};. 



PLACOBRANCHUS, Van Hasselt. 



Two tentacula and as many labial lobes ; the whole back, widened 

 by its margin, is covered with numerous radiating striae, which are 

 the branchiae. In its ordinary condition the widened borders of the 

 mantle are turned up, and cross each other to form an envelope for 

 the branchiae, which are thus enclosed, as in a cylindrical case. 

 They are small Mollusca, from the Indian Ocean ||. 



ORDER III. 



INFEROBRANCHIATA. 



The Inferobranchiata have nearly the same form and organization 

 as are observed in Doris and Tritonia, but their branchiae, instead of 

 IMMHU placed on the back, resemble two long series of laminae, situated 

 on the two sides of the body, under the projecting margin of the 

 mantle. 



* Doris affinis, Cm. Carol., Polyp. Mar., VII, 4. 



f l,imtuc ttryipta, Forsk., XXVI, E, or Doris lacinulata, Gm. ; Doris macu- 

 lala, Lin. Trans., VII, Til. 34 ; Doris ptnnala, Bomml, Act. Fless., I, Hi, 3. 



J Busiris grisctts, Risso, Hist. Nat. Mar., IV, pi. i, f. 6. 



|| In the species known (Placobranchus Hassclti, Cnv.), the branchial stria: are 

 preen, and the body a brown-grey sprinkled with little ocelli. Van llas^clt., Bui 

 let. 1,m <>,t.. 1824, p. 240. Messrs Quoy and Gayraard found It at the 

 Fiu-mlly Islands. 



